The present invention relates generally to luminaires and more particularly to a specific luminaire, a specific luminaire reflector and a specific luminaire refractor especially suitable for lighting a given straight roadway section from a point a substantial distance to one side of and above the roadway.
Today, most roadways and particularly expressways such as interstate highways that are lighted are done so with conventional luminaires supported on poles mounted at or in close proximity to one curb of the roadway. The poles positioned in this manner produce an obvious and definite collision hazard condition to oncoming vehicles, especially on crowded and fast-moving modern day expressways. As will be seen below, there have been several attempts to eliminate or minimize this hazardous condition. However, for various reasons, these attempts have not been completely successful.
One suggested solution to minimize the aforedescribed hazardous condition has been to provide the luminaire pole with a frangible base so that when the base is hit by an oncoming vehicle it breaks off, presumably without causing much damage to the vehicle or bodily harm to the occupant or occupants. This suggested solution has several obvious disadvantages. In the first place, the maintenance required in replacing these collided poles and the supported luminaires as a result of the collision would be extremely high and, in fact, economically impractical. In the second place, there would be some and possibly a large amount of property damage to the vehicle as a result of the collision. In the third place, the falling pole quite possibly could strike another vehicle on the roadway or the driver of the colliding vehicle could lose even greater control of his vehicle as a result of the collision.
Another suggested solution which would eliminate completely the aforedescribed hazardous condition has been to mount the poles on a solid concrete median such that the poles are located above the point at which they would interfere with oncoming vehicles. This would, of course, eliminate any possibility of collision. However, to provide medians, which do not already exist or which are not otherwise suitable, would be economically impractical.
A further suggested solution has been to place the luminaire poles a substantial distance to one side of the roadway, for example 30 feet, and to mount their associated luminaires directly above the roadway by utilizing extremely long mast arms extending from the poles. This, too, is economically impractical, mainly because the mast arms to support the luminaires would have to be extremely strong and very expensive. In this regard, there have been suggestions to eliminate or substantially shorten the mast arms and position the luminaires a substantial distance to one side of the roadway, that is, at or at least in close proximity to the remotely positioned poles. This has not been found to be a satisfactory solution because conventional luminaires are designed to be mounted at the edge of the roadway and do not efficiently or effectively light the roadway from such remote off-the-roadway points.
As will be seen hereinafter, the present invention eliminates the aforedescribed hazardous condition by positioning the luminaire poles a substantial distance to one side of the roadway as previously suggested. However, unlike the last-mentioned suggested solution, the present invention includes a specifically designed luminaire and, in fact, a specifically designed reflector and refractor especially suitable for off-the-roadway use without appreciably compromising the quantity or quality of light placed on the roadway.